Frequency transposing hearing aid

Abstract

The described hearing aid includes a frequency analyzer for classifying incoming sounds according to their frequency, and for selecting an appropriate transposition factor (the ratio of the information storage rate to the information retrieval rate) according to the appropriate one of several transposition factors inputted into the hearing aid based on the particular user's hearing characteristics for different frequencies. Also, described is an arrangement for minimizing loss of speech components containing the same frequency information by recirculating such speech components. Further described is an arrangement for reconstructing portions of the speech components according to their classification by the frequency analyzer in order to minimize loss of useful information in the output signal.

I claim: 
     
       1. Hearing aid apparatus to facilite hearing by a user, comprising: converting means for converting inputted audio frequency sounds to electrical input signals;   storage means for storing information associated with said electrical input signals; and   control means for controlling the storage means to store information at a predetermined information storage rate and to output the stored information at a predetermined information retrieval rate, the ratio of the information storage rate to the information retrieval rate being termed the transposition coeffecient;   said control means including input means for inputting at least two different transposition coefficients predetermined according to the user's hearing characteristics for different frequencies;   frequency analyzer means for classifying incoming audio frequency sounds according to their frequency and to select the appropriate transposition coefficient according to the frequency of the incoming signal; and   clock generator means for generating clocking signals applied to said storage means at a clock rate determining the information storage rate and the information retrieval rate according to the selected transposition coefficient.   
     
     
       2. Hearing aid apparatus according to claim 1, wherein said storage means comprises a pair of storage devices. 
     
     
       3. Hearing aid apparatus according to claim 2, wherein said storage devices comprise a pair of analog delay lines configured in a switched push-pull arrangement, whereby controlled by said clocking signals such that one delay line stores input information at one clock rate while information is retrieved at the output of the other delay line at a different clock rate. 
     
     
       4. Hearing aid apparatus according to claim 2, wherein said storage devices comprise a pair of memory devices each including an analog-to-digital converter at its input, and a digital-to-analog converter at its output, said memory devices being controlled by said clocking signals such that one memory device stores input information at one clock rate while information is retrieved at the output of the other memory device at a different clock rate. 
     
     
       5. A hearing aid according to claim 1, wherein said control means further includes recirculating means for recirculating information originally stored in the storage means back to the storage means. 
     
     
       6. A hearing aid according to claim 1, wherein said control means is operative to lower the frequencies contained within speech components of said inputted audio frequency sounds by using an information retrieval rate which is less than the information storage rate. 
     
     
       7. A hearing aid according to claim 1, wherein said control means is operative to raise the frequencies contained within speech components of said inputted audio frequency sounds by using an information retrieval rate which is greater than the information storage rate. 
     
     
       8. A hearing aid according to claim 1, wherein said control means further includes reconstruction means for reconstructing the inputted audio frequency sounds while preserving the frequency pattern of such inputted audio frequency sounds by controlling the storage of only portions thereof according to their classification by said frequency analyzer means, the time period of each portion being proportional to the transposition coefficient. 
     
     
       9. A hearing aid according to claim 1, wherein said control means further includes approximator means which is operative to combine the stored information output from said storage means at the time of switching between retrieval and storage in order to smooth the output from said storage means. 
     
     
       10. A hearing aid according to claim 1, wherein said control means further includes a noise generator operative to constantly vary by a small amount said transposition coefficient. 
     
     
       11. Hearing aid apparatus comprising: converting means for converting inputted audio frequency sounds to electrical input signals;   storage means for storing information associated with said electrical input signals;   and control means for controlling the storage means to store information at a predetermined information storage rate and to output the stored information at a predetermined information retrieval rate;   said control means comprising a frequency analyzer for classifying incoming audio frequency sounds according to their frequency, and recirculating means for recirculating information originally stored in the storage means back to the storage means.   
     
     
       12. The apparatus according to claim 11, wherein said control means is operative to lower the frequencies contained within speech components of said inputted audio frequency sounds by using an information retrieval rate which is less than the information storage rate. 
     
     
       13. The apparatus according to claim 11, wherein said control means is operative to raise the frequencies contained within speech components of said inputted audio frequency sounds by using an information retrieval rate which is greater than the information storage rate. 
     
     
       14. The apparatus according to claim 11, wherein said control means further includes approximator means which is operative to smooth the stored information outputted from said storage means. 
     
     
       15. The apparatus according to claim 11, wherein said control means further includes: input means for inputting at least two different transposition coefficients representing the ratio of the information storage rate with respect to the information retrieval rate, which transposition coefficients are predetermined according to the user's hearing characteristics for different frequencies;   said frequency analyzer being operative to classify incoming radio frequency sounds according to their frequency and to select the appropriate transposition coefficient according to the frequency of the incoming signal;   said control means further including clock generator means for generating clocking signals applied to said storage means at a clock rate according to the selected transposition coefficient.   
     
     
       16. The apparatus according to claim 11, wherein said control means further includes reconstruction means for reconstructing the inputted audio frequency sounds while preserving the frequency pattern of such inputted audio frequency sounds by controlling the storage of only portions thereof according to their classification by said frequency analyzer means, the time period of each portion being proportional to the transposition coefficient. 
     
     
       17. Hearing aid apparatus comprising: converting means for converting inputted audio frequency sounds to electrical input signals;   storage means for storing information associated with said electrical input signals;   and control means for controlling the storage means to store information at a predetermined information storage rate and to input the stored information at a predetermined information retrieval rate;   said control means including a frequency analyzer for classifying incoming audio frequency sounds according to their frequency, and reconstruction means for reconstructing the inputted audio frequency sounds while preserving the frequency pattern of such inputted audio frequency sounds by controlling the storage of only portions thereof according to their classification by said frequency analyzer means, the time period of each portion being proportional to the transposition coefficient.   
     
     
       18. The hearing aid according to claim 17, wherein said control means further includes: input means for inputting at least two different transposition coefficients representing the ratio of the information storage rate with respect to the information retrieval rate, which transposition coefficients are predetermined according to the user's hearing characteristics for different frequencies;   said frequency analyzer being operative to classify incoming audio frequency sounds according to their frequency and to select the appropriate transposition coefficient according to the frequency of the incoming signal;   said control means further including clock generator means for generating clocking signals applied to said storage means at a clock rate according to the selected transposition coefficient.   
     
     
       19. The hearing aid according to claim 17, wherein said control means further includes approximator means which is operative to smooth the stored information outputted from said storage means. 
     
     
       20. The hearing aid according to claim 17, wherein said control means is operative to lower the frequencies contained within speech components of said inputted audio frequency sounds by using an information retrieval rate which is less than the information storage rate. 
     
     
       21. The hearing aid according to claim 17, wherein said control means is operative to raise the frequencies contained within speech components of said inputted audio frequency sounds by using an information retrieval rate which is greater than the information storage rate.